Abstract
Concentrations of 137Cs and stable Cs in wild mushrooms, cultivated mushrooms and those substrates were measured by gamma-ray spectrometry and neutron activation analysis.
The average concentration of 137Cs in 80 wild mushrooms in Japan was 87.5Bq/kg (wet wt.), and concentration of 137Cs in mycorrhizal mushrooms was higher than that of saprophytic mushrooms. High concentrations of 137Cs were found in Pleurotus ostreatus (Fr.) Kummer Y-1, saprophytic mushrooms, cultivated in culture substrates containing high 137Cs. Clear correlations with 5% level of significance were found between wild mushroom-to-substrate ratios (wet/dry) of 137Cs concentration and those of stable Cs. Cultivated P. ostreatus-to-culture substrate ratios (wet/wet) of 137Cs concentration were stable in the order of 100 when the culture substrate was containing 10000Bq/kg (wet wt.) of 137Cs or 1000mg/kg (wet wt.) of stable Cs. The ratios of 137Cs concentration in cultivated mushrooms were about equal to those in wild mushrooms. Higher concentration of 137Cs in culture substrate after sampling P. ostreatus was observed at the upper layer where mycelium density was high.
